SHANKSVILLE, Pa. (AP)  Former House Speaker Dennis Hastert gave the flag that flew atop the U.S. Capitol on 9/11 to the Flight 93 National Memorial on Thursday, saying the building might not still be standing if the plane’s passengers and crew had not rebelled against four hijackers.Hastert spoke to hundreds of family members, dignitaries and spectators at a ceremony in a field in Shanksville, Pennsylvania, where the United Airlines plane crashed on Sept. 11, 2001.Hastert, who was speaker of the House on that day, said the donated Stars and Stripes has smoke smudges from the fire caused by another hijacked plane flown into the Pentagon.”Today that flag would not have been in existence … if not for the great heroes who we’ll hold in our hearts for ever and ever,” he said.Flight 93 was traveling from Newark, New Jersey, to San Francisco when al-Qaeda-affiliated terrorists took control, with the likely goal of crashing it into the White House or Capitol. The 9/11 Commission concluded the hijackers downed the plane in southwestern Pennsylvania as the 33 passengers and seven crew members revolted. Two other hijacked planes destroyed the World Trade Center in New York.The 13th anniversary of the attacks comes as the National Park Service marks progress on a $17 million to $23 million phase of the Flight 93 memorial. Official hope the project, which includes a visitors’ center and learning space, will boost the number of annual visitors to the site from 300,000 to more than 500,000.”We have to make sure there will be a place to come in the future to learn about what happened,” Gordon Felt said Thursday. Felt’s brother, Edward, was among the passengers killed.At the ceremony, the victims were posthumously awarded a Congressional Gold Medal, the nation’s highest civilian honor. The medal will be displayed temporarily at the memorial through Sunday, and will be part of a permanent exhibit once the visitors’ center opens  hopefully next year.The same medals are being awarded at the Pentagon and World Trade Center sites.Rachel Stingis, 30, of Belle Vernon, was among the first spectators to arrive in Shanksville. Stingis had visited the site before the memorial was built, but never attended an anniversary ceremony. She said she was in high school at the time of the attacks and watched the coverage on television in class.”Being a senior ready to start college, I thought it was the end of the world,” she said.A Memorial Plaza near the plane crash site consists of a white stone wall that traces the doomed plane’s flight path, with each victim’s name engraved on a separate panel. There are plans for a 93-foot-tall tower with 40 wind chimes.